Aircraft turbine supercharger



Dec. 26, 1944 D. R SHOULTS AIRCRAFT TURBINE SUPERGHARGER Filed Feb. 14,1942

Invmcorv David Shoults,

' l-hs Attorney.

Patented Dec. 26, 1944 PATENT oF lcE AIRCRAFT TURBINE surnacmona.

DavidR. Shoults, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application February 14, 1942, Serial No. 430,881

force gases issuing from the buckets on the upstream side of'the wheel toward the central portion thereof, thus causing heating of the wheel. AIsmafter-burning of the gases issuing from the turbine wheel may occur.

One object of the present invention is toprovide an improved construction and arrangement for protecting the turbine wheel from the hot exhaust gases, which effects a smooth and even turning of the gases after they leave the wheel into the slip stream, and which interferes to a minimum with'the radiation of lheat from the turbine buckets. v

A further object of the invention'is-to provide means whereby the parts which serve to direct the hot exhaust gases from the buckets into the slip stream are cooled by air from' the slip stream.

A-further object of my invention is to provide an improved arrangement for accomplishing the foregoing which is simple in structure, emcient in operation and light in weight.

For a consideration of what I believe to be novel and my invention, attention is directed to the following spec'iflcationand the claims appended thereto.

In the drawing, Fig. 1 is a face view of a structure embodyingmy invention; Fig. 2 is ayertical sectional view thereof: and Fig. 3 is'a top plan view partly in section.

Referring to the drawing, I indicates the shaft.

of 'a supercharger which iscarried in a suitable bearing (not shown) and has overhung on its end a turbine wheel comprisinga central disk 3 on the periphery of which is aring of buckets 4 having at their outer ends a shroud band I. Gases from theengineor' from other source of supply are directed against the buckets by nozzles i which form apart of a nozzle box "I." The exhaust gases are supplied to the nozzle box through a suitable conduit (not shown) connected with a source of supply suchas, for example. the exhaust manifold of an lnternal combustion engine. Only sufllcient of the supercharger has been illustrated as is required for an understanding of my invention. It is to be taken as typical of any suitable gas driven turbine construction. The gas is discharged from the turbine wheel in the direction indicated by arrows 8 in Fi 2. The direction of the slip stream is indicated by the arrow 8 in Fig. 2. According to my invention, I provide protecting means for the turbine wheel, termed usually a cooling cap or flighthood, comprising two dished disk-shaped walls It) and II joined along their edges 'as is indicated at I! and spaced apart suf- -flciently to define a cooling air chamber l3 of the desired size. Inner wall I is of a diameter equal substantially to that of the turbine wheel disk 3. Outer wall H is curved downward at its 1. upper or upstream portion as is indicated at I4 and depends downward somewhat beyond wall I 0 as is indicated at It. It provides a smoothly curved surface. over which gases discharged from the upstream or top side of the turbine may flow. Surrounding walls Ill and II in spaced relation thereto is a downwardly curved cylindrical wall I! provided with an annular U-shaped flange H. The axial depth of cylindrical wall it at its upper end is indicated by line l8. (Fi 1) and at its lower end by line is (Fig. 1). Cylindrical wall l6 at its inner edge 2|) has a diameter slightly greater than that of the turbine wheel and forms with wall H a downwardly curved annular passage 2| through which gases discharged from the turbine wheel flow into the slip stream. Referring particularly to Fig. 1, it will be seen that cylindrical wall Ii is'of relatively small axial depth, it being of substantially uniform axial depth throughout its circumference, and that it covers only a minor portion of the bucket ring, the major portion being uncovered whereby. gases from such major portion are discharged directly to atmosphere and heat from such major portion may radiate directly to atmosphere.

Flange I1 is fastened to the nozzle box by a second flange 22 which is fixed to the nozzle box .byaringofbolts 23. e

Extending acrossfiannular. passage 2! between shown in Fig. 2, are curved downwardly toturn the exhaust gases issuing from the turbine buckets and directthem into theslip stream.

lanes are attached to walls I! and [8 preferably by welding. They are hollow and the hollow spaces communicate at one end with air walls I and." are'a'plurality of exhaust gas directing and cooling vanes 24 which, as best upper or upstream side is an inlet pipe or ram 25 which faces in the direction of the slip stream and serves to convey air from. the atmosphere to chamber l3. At the lower ordownstream side oi chamber I8 is a narrow air discharge conduit II; Also. at their lower or downstream sides, walls It and II are shaped to provide a narrow elongated slot i'l to: discharge or air against the rim of the turbine wheel disk for cooling it.

vanes 24 and conduits 2i and II serve to hold cylindrical wall I! and walls ii and I! in assembled relation, the structure as a whole being supported, at least in part, from the nozzle box by theringoiboltsfl;

In operation, gases issuing from the buckets of the turbine wheel are turned by the upstream portion wall it and byvanes 24 and are directed across the wheel and into the slip stream. This serves to eilect a gradual turning oi the gases and their smooth even how into the slip stream. Thus the flow of the exhaust gases into the slip stream interferes to a minimum with the distribution of the slip stream air flow over the turbo-supercharger installation Ifhe flighthood comprising walls 10 and ii serves to prevent exhaust gases coming into direct contact-with wheel disk 8 and to prevent any after-burning adjacent to the Wheel. 0001- ing air enters chamber ilfthro'ugh conduit and flowsoutwardly throughhollow vanes 24 to cool the vanes. Also air flows through slot 21 against the rim oi'the webio cool it and the buckets. The cooling air also absorbs heat from the wheel through wall l0 carries it away.

By my invention} p ov de an improved construction which is light in weight, which eflectively protects the wheel from the hot exhaust gases, which prevents after-burning adjacent to 1. The combination with a gas turbine wheel comprising a disk with buckets thereon, of cooling and protecting means therefor comprising spaced walls which form a shield for the disk of the wheel and provide a cooling air chamber, a cylindrical wall which surrounds the firstnamed walls in spaced relation thereto to provide a discharge passageior gases issuing from the turbine wheel buckets, gas-directing vanes in said discharse passage having transverse passages which communicate with said cooling air chamber, and means for eilecting flow oi cooling air through said cooling air chamber and said transvers passages.

'2. The combination with a. gas turbine wheel comprising a disk with buckets thereon, oi cool,-

ing and protecting means therefor comprising spaced walls which form a shield for the disk oi the wheel and provide a cooling air chamthrough aid cooling air chamber and said transverse passages, and means defining a passage for discharging cooling air from said cooling air chamber against the wheel.

3. The combination with a turbo-supercharger gas turbine wheel comprising a disk with buckets thereon for mounting on an aircrait in a position such that the slip stream of the aircraft flows 86 transversely across it, of cooling and protecting the wheel and which iunctionsto cool the wheel in a satisfactory manner.

ent'statutes, I have described the principle oi operation or my inventipn, together with the ap- -paratus which I now consijdento represent the whatlclaimasnewanddesiretosecure by 0 Letters raht oi the United" stilteaisz means therefor comprising spaced walls which form a shield for the disk or the wheel and provide a cooling air chamber, a cylindrical wall which surrounds the first-named walls in spaced e 40 relation thereto and is curved in the direction oi In accordance with the provisions of the pat- 01' relatively small axial depth and covering only a minor portion or the bucket ring, and gas directing vanes in said discharge passage.

mvm a. snouurs.

46 into the slip stream, said cylindrical wall being. 

